Recently, as international crude oil prices sharply rises, attention is focused on hydrogen energy as a promising substitute energy source.
The hydrogen energy can be obtained from water and is a clean energy that does not cause pollution. Thus, the hydrogen energy may be considered as a promising energy source which is substituted for fossil fuels such as oils and solves an energy crisis. In particular, the hydrogen, unlike the fossil fuels such as oils and natural gas, can generate energy without emission of carbon dioxide and be recycled into water after use as an energy source. Thus, the hydrogen energy is eco-friendly and is an energy source without concern of resources exhaustion.
For commercially applying the hydrogen as an energy source, it is necessary to develop and provide gas storage material or medium having superior gas storage efficiency for the hydrogen gas. In particular, the gas storage material should stably store gas, and effectively release the stored gas when use of the gas is needed.
Recently, there are some researches for various gas storage materials of the hydrogen or methane. These gas storage materials use natural porous inorganic materials such as zeolite or carbon nanotube; various metal-organic frameworks (MOFs) having pore structures; or metal or alloy hydrides such as LiAlH4, KBH4, FeTiH2, Mg2NiH4, MgH2 or LaNi5H6. However, most of the conventional gas storage materials can not have sufficient gas storage efficiency. Further, even a few metal-organic composites having sufficient gas storage efficiency cannot maintain stable gas storage state, or cannot properly release the stored gas when needed [Nature 1999, 398, 796; Nature 2002, 416; Science 2004, 306 1021; Acc. Chem. Res. 2002, 35, 972; WO09/011,545; WO06/110740; WO09/010,945; US Pat. Application 20100015026; WO01/78886; J. Colloid & Interface Science, 2008, 318, 42; Nature 2001, 414, 353; Angew. Chem. Int'l. 2006, 45, 7358; J. Am. Chem. Soc. 2008, 130, 7848; CARBON, 2009, 47, 3346; International Journal of Hydrogen Energy, 2010, 35, 225; Chem. Rev. 2007, 107, 4111; US Patent Application #20020034471; J. Korean Ind. Eng. Chem., 2009, 20(5), 465; US department of energy (DOE), DOE Hydrogen Program, FY, Program Review, 2004].